US6543966B2 - Drive system for inserting and extracting elongate members into the earth - Google Patents

Abstract

A drive system for elongate members comprising a drive plate, a support system, an insertion housing, at least one drive gear, and a vibratory system. The suppression system resiliently opposes relative movement between the support plate and the insertion housing. The drive gear displaces the elongate member along its longitudinal axis. The vibratory forces are transmitted to the elongate member through the at least one drive gear. The drive gear and the vibratory system simultaneously crowd and vibrate the elongate member into the ground.

Description

RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 09/415,042 filed on Oct. 7, 1999, abandoned which is a continuation-in-part of U.S. patent application Ser. No. 08/900,481, which was filed on Jul. 25, 1997, now U.S. Pat. No. 6,039,508, and also claims priority of U.S. Provisional Application No. 60/122,151, which was filed on Feb. 26, 1999.

TECHNICAL FIELD

The present invention relates to methods and apparatus for inserting into the earth and extracting from the earth elongate members and, more particularly, to apparatus and methods for inserting wick drain material into the earth.

BACKGROUND OF THE INVENTION

For certain construction projects, elongate members such as piles, anchor members, caissons, and mandrels for inserting wick drain material must be placed into and in some cases withdrawn from the earth. It is well-known that, in many cases, such rigid members may be driven into and withdrawn from the earth without prior excavation.

The present invention is particularly advantageous when employed to insert a mandrel carrying wick drain material into the earth, and that application will be described in detail herein. However, the present invention may have broader application to the insertion into and removal from the ground of other elongate members such as piles, anchor members, and caissons, especially when these members must be driven at an angle with respect to horizontal. Accordingly, the scope of the present invention should be determined by the scope of the claims appended hereto and not the following detailed description.

Because wick drain material is flexible, it cannot be directly driven into the earth. Instead, it is normally placed within a rigid mandrel that is driven into the earth. Once the mandrel and wick drain material have been driven into the earth, the mandrel alone is removed from the earth, leaving the wick drain material in place. The wick drain material that is left in place wicks moisture in its vicinity to the surface to stabilize the ground at that point.

Two basic systems are employed to drive mandrels into and remove mandrels from the earth. A first system is referred to as a top drive system and engages the upper end of the mandrel to insert the mandrel into the earth. In a top drive system, the upper end of the mandrel is securely attached to the drive system and forced downward or upward to insert the mandrel into or remove the mandrel from the ground. The upper end of the mandrel may also be vibrated by a vibratory drive means and/or crowded by a chain or cable drive means to cause the mandrel to penetrate the earth.

The primary disadvantage with the top drive system is that they require a substantial boom structure to support the mandrel and associated drive means. The requirement of a large and heavy boom structure limits the length of the mandrel that may be driven by a top drive system. Further, as the ground into which the wick drain material is to be inserted may be wet and unstable, the ground may not be sufficiently stable to support the required boom structure. Top drive systems thus may be inappropriate in certain situations.

A second system for inserting and removing mandrels engages the bottom end of the mandrel and will be referred to herein as a bottom drive system. A bottom drive system is not attached to any one point on the mandrel; instead, rotating roller surfaces and/or gear teeth engage the mandrel in a manner that displaces the mandrel along its axis to drive it into the ground.

Bottom drive systems require a boom sufficient to support only the mandrel; the boom for a bottom drive system may thus be significantly lighter than that for a top drive system, which alleviates some of the problems associated with large booms.

However, the primary disadvantage with known bottom drive systems is that they rely entirely on the roller or gear drive system for insertion and removal of the mandrel. Bottom drive systems do not have the benefit of a vibratory device for situations in which the mandrel becomes stuck due to soil conditions.

Accordingly, an important object of the present invention is to provide improved apparatus and methods for driving elongate members into and removing elongate members from the ground.

RELATED ART

U.S. Pat. No. 5,213,449 to Morris shows, and USSR Patent No. SU 1027357 appears to show, bottom drive devices for driving a mandrel into the ground. The Morris patent discloses a gear dive system and the USSR patent appears to show a roller drive system.

Top drive wick drain inserters are disclosed in U.S. Pat. No. 3,891,186 to Thorsell, U.S. Pat. No. 4,166,508 to van den Berg, U.S. Pat. No. 4,755,080 to Cortlever et al., Dutch Pat. No. 65252, Dutch Pat. No. 7805153, and Dutch Pat. No. 7,707,303.

The Thorsell patent employs a chain attached to the top of a wick drain mandrel to crowd the mandrel into the ground.

The van den Berg patent employs a two-part mandrel, with the two parts being wound around rollers and crowded into the ground by unwinding the rollers.

The Cortlever et al. patent discloses a cable connected to the upper end of the mandrel and a hydraulic system for displacing the cable to drive or crowd the mandrel into the ground.

The Dutch '252 and '153 patents appear to employ a chain to drive or crowd a mandrel into the ground.

In the Dutch '703 patent, a vibratory device appears to be fixed to the top end of the mandrel to drive the mandrel into the ground.

Shown in U.S. Pat. Nos. 5,117,544 and 5,117,925 issued to the Applicant are vibratory devices for driving piles into the earth. These patents disclose placing the vibratory device on top of the pile to be driven and vibrating the pile along its axis; the combination of the vibratory forces along the axis of the pile and the weight of the pile and vibratory device drives the pile into the ground. Caissons may be driven into the ground in the same manner.

SUMMARY OF THE INVENTION

The present invention is a drive system for inserting an elongate member into the ground. The drive system comprises a drive plate, a support system, an insertion housing, at least one drive gear, and a vibratory system for creating vibratory forces. The support system that engages the ground and supports the support plate at a substantially fixed height above a desired location. The suppression system is operatively connected between the support plate and the insertion housing to support the insertion housing above the desired location and resiliently oppose relative movement between the support plate and the insertion housing. The at least one drive gear is mounted to the insertion housing and engages the elongate member such that rotation of the drive gear displaces the elongate member along its longitudinal axis. The vibratory system is mounted to the insertion housing such that the vibratory forces are transmitted to the elongate member through the at least one drive gear. Rotation of the drive gear crowds the elongate member into the ground. Operation of the vibratory system vibrates the elongate member into the ground. Rotation of the drive gear and operation of the vibratory system together crowds and vibrates the elongate member into the ground.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side plan view of a first elongate member insertion/removal system that is constructed in accordance with the principles of the present invention;

FIG. 2 is a perspective view of the vibratory assembly, gear drive assembly, and shock absorbing assembly of the system depicted in FIG. 1;

FIG. 3 is a side plan view of the assemblies depicted in FIG. 2;

FIG. 4 is a top plan view of a portion of a second exemplary elongate member insertion/removal system that is constructed in accordance with the principles of the present invention;

FIG. 5 is a side plan view of a portion of a third exemplary elongate member insertion/removal system that is constructed in accordance with the principles of the present invention;

FIG. 6 is a top plan view of a portion of a third exemplary elongate member insertion/removal system that is constructed in accordance with the principles of the present invention;

FIG. 7 is a vertical section view of an insertion assembly constructed in accordance with, and embodying, the principles of the present invention;

FIG. 8 is a front plan view of the insertion assembly of FIG. 7;

FIG. 9 is a top plan view of the insertion assembly of FIG. 7 with background details omitted for clarity; and

FIG. 10 is a top section view taken along lines10—10 in FIG. 8, again with background details omitted for clarity;

FIG. 11 is a somewhat schematic side elevation view of yet another exemplary elongate member insertion/removal system that is constructed in accordance with the principles of the present invention;

FIG. 12 is a section view of the upper end of a mandrel being driven by the system of FIG. 11 depicting an interaction between the mandrel and a wind sleeve that protects the wick material above the mandrel;

FIG. 13 is a section view of the lower end of the wind sleeve of the system of FIG. 11 depicting the interaction between the mandrel and the wind sleeve;

FIG. 14 is a somewhat schematic side elevation view of still another exemplary elongate member insertion/removal system that is constructed in accordance with the principles of the present invention; and

FIGS. 15A and 15B are front elevation section and side elevation views, respectively, depicting an indicator system of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

1. First Embodiment

Turning now to the drawing, depicted at20 in FIG. 1 is an elongate member insertion/withdrawal system constructed in accordance with, and embodying, the principles of the present invention. Thesystem20 is designed to insert into and remove from the ground22 amandrel24 carryingwick drain material26, but other elongate members may be driven by thesystem20 in a similar manner.

Theexemplary system20 comprises asupport assembly28, avibratory assembly30, agear drive assembly32, and ashock absorbing assembly34. Thesupport assembly28 comprises asupport base36, amast38, andmandrel support40. Thesupport base36 is designed to engage asurface42 of the ground22 and provide a solid, stable surface for supporting themast38. Thesupport base36 can be a self-propelled platform such as a tracked vehicle or may, as shown, be placed directly onto theground surface42.

Themast38 vertically extends from thesupport base36, and the mandrel supports40 horizontally extend from vertically spaced locations on themast38. Themandrel24 is encircled by the mandrel supports40 before and during insertion of themandrel24 into the ground22. Thesupport assembly28 thus maintains themandrel24 in a desired orientation with respect to the ground; in theexemplary system20, this desired orientation is vertical.

Thevibratory assembly30 is located in a channel44extending from top to bottom through thesupport base36. Theshock absorbing assembly34 mounts thevibratory assembly30 within thechannel44 in a manner that: (a) maintains thevibratory assembly30 in a desired location relative to the ground22; and (b) absorbs vibratory forces generated by thevibratory assembly30 and thus reduces the transmission of these forces to the support means. Thevibratory assembly30 is thus free to vibrate up and down within thechannel44, and only acceptably low levels of vibration are transmitted to thesupport base36.

Referring now to FIGS. 2 and 3, depicted in more detail therein are themandrel24, thevibratory assembly30, thegear drive assembly32, and theshock absorbing assembly34.

Referring initially to thevibratory assembly30, FIG. 3 shows a conventional vibratory assembly comprises first and secondeccentric weight members46 and48 fixed ontovibratory shafts50 and52 mounted within ahousing54. Thevibratory shafts50 and52 are horizontal and parallel to each other.

To cause thehousing54 to vibrate, thevibratory shafts50 and52 are rotated by motors (not shown) at the same speed in opposite directions, which causes theeccentric members46 and48 to rotate about the axes of theseshafts50 and52. Theeccentric members46 and48 are mounted on thevibratory shafts50 and52 such that: (a) the lateral forces on the housing54 (in the direction of arrow B in FIG. 3) generated by theeccentric members46 and48 substantially cancel each other; while (b) the vertical forces on the housing54 (in the direction of arrow A in FIG. 3) generated by theeccentric members46 and48 are added to each other and transmitted to thehousing54. The result is that this rotation of theeccentric members46 and48 causes thehousing54 to vibrate with great force along a vibratory axis in the vertical direction and very little in the lateral direction.

Thegear drive assembly32 is perhaps best shown in FIG.2. Thegear drive assembly32 basically comprises first andsecond bracket assemblies56 and58, first andsecond drive shafts60 and62, and first and second drive gears64 and66, and first and second drive racks68 and70. Thebracket assemblies56 and58 are securely attached to anupper surface72 of thevibratory housing54. Thedrive shafts60 and62 are mounted on thebracket assemblies56 and58, respectively, above thehousing surface72 such that theshafts60 and62 can be rotated about their axes. The drive gears64 and66 are mounted on thedrive shafts60 and62 such that thegears64 and66 are securely held at a fixed distance above thehousing surface72.

The first and second drive racks68 and70 are formed onopposite surfaces74 and76 of themandrel24. Themandrel24 extends through avertical mandrel passageway78 formed in thehousing54 such that theracks68 and70 engageteeth64aand66aof the drive gears64 and66.

Accordingly, rotation of thedrive shafts60 and62 in the opposite direction by a motor (not shown) causes the drive gears64 and66 to rotate, which in turn causes thegear teeth64aand66ato engage the drive racks68 and70 to displace themandrel24 along its lengthwise axis C (FIG.2). In this fashion, themandrel24 can be moved either up or down along its axis C relative to thevibratory housing54.

At this point, it should be noted that the unshown motors employed to turn thevibratory shafts50 and52 and thedrive shafts60 and62 are preferably direct fluid to torque hydraulic motors. The motors should be able to withstand severe vibration because they must be mounted on thevibratory housing54, and direct fluid to torque motors are much less susceptible to vibration damage than hydraulic motors employing a planetary gear. Appropriate direct fluid to torque hydraulic motors are available from, for example, POCLAIN under the model name CAM TRACK. The source of the pressurized fluid employed to drive these motors is preferably mounted on thesupport base36 and connected to the hydraulic motors via flexible hoses. This arrangement of hydraulic motors and fluid source minimizes: (a) the amount of equipment that is directly subjected to the vibratory forces generated by thevibratory assembly30; and (b) the damage to the equipment that is subjected to these vibratory forces.

Referring now to FIGS. 2 and 3, these Figures show that theshock absorbing assembly34 comprises eight rectangular solid shock absorbing members80 (only seven shown in FIG. 2) that are flanged such that they can be bolted to thevibratory housing54 and thesupport base36. Thesemembers80 are made of strong, resilient, rubber-like material. When thevibratory housing54 vibrates up and down, theseshock absorbing members80 allow the housing to move up and down a short distance relative to thesupport base36; in doing so, themembers80 yieldingly resist the transmission of vibratory forces from thevibratory housing54 to thesupport base36. Accordingly, theshock absorbing assembly34 effectively isolates the support base from the vibratory forces generated by thevibratory assembly54.

In operation, themandrel24 will initially be arranged with a lower end24athereof adjacent to thesurface42 of the ground22 and with thewick drain material26 loaded therein. Thedrive shafts60 and62 will then be rotated to cause themandrel24 to enter the ground22. The downward force applied by thegear drive assembly32 may in many cases be sufficient to drive themandrel24 to the desired depth.

However, in some cases, the soil conditions of the ground22 may be such that the force applied by thegear drive assembly32 is insufficient and themandrel24 can not be inserted into or withdrawn from the ground22. In these cases, thevibratory shafts50 and52 may be rotated to cause thevibratory housing54 to vibrate up and down. These vibratory forces will be transmitted to themandrel24 at the points where theteeth64aand66aof the drive gears64 and66 engage the drive racks68 and70. Themandrel24 will thus be vibrated up and down along its axis C. Such vibration is extremely effective at overcoming resistance to the insertion and withdrawal of themandrel24.

Further, the vibratory forces generated by thevibratory assembly30 may be applied at the same time as the drive forces generated by thegear drive assembly32; thegear drive assembly32 is mounted on thevibratory housing54 and will move up and down at the same rate as thevibratory housing54. The combination of a driving force and a vibratory force can greatly increase the speed at which themandrel24 is inserted into and withdrawn from the ground22.

The elongate member insertion/withdrawal system20 thus exhibits all of the benefits of a bottom drive system as described above but in addition allows the use of vibratory forces when soil conditions require such forces and simply to speed up the process of inserting or removing wick drain mandrels.

Several features of the insertion/withdrawal system20, while not essential to the operation of the present invention, are believed to optimize the implementation of the present invention and will now be discussed in further detail.

For example, FIGS. 2 and 3 both show that thevibratory assembly30 is substantially symmetrically arranged about the axis C of themandrel24. More particularly, as shown in FIG. 3 theeccentric members46 and48 andshafts50 and52 connected thereto are arranged the same distance from the mandrel axis C, with theshafts50 and52 orthogonal to this axis C. With this arrangement, the vibratory forces are applied along the mandrel axis C. Without such symmetry, the vibratory forces would cause a torsional load to be exerted on themandrel24. Such a torsional load would increase the stress on themandrel24 and/or thegear drive assembly32 that engages themandrel24 and thus the likelihood of damage thereto.

Another optional feature of the present invention is the location of the drive gears64 and66 relative to themandrel24. The lateral forces applied on themandrel24 by thesegears64 and66 are in opposite directions along a line D shown in FIG.3. With this arrangement, it is not necessary to pinch themandrel24 at two points in order to displace it along its axis; instead, thegears64 and66 need only apply sufficient lateral loads to maintain themandrel24 at the center of thepassageway78. This eliminates the need to place a constant load on themandrel24 and thus reduces stresses thereon. The placement of thegears64 and66 also mean that the vertical vibratory forces transmitted to themandrel24 are applied in a symmetrical fashion that alleviates twisting of themandrel24. The lateral forces applied on themandrel24 by thesegears64 and66 are in opposite directions along a line D shown in FIG.3. With this arrangement, it is not necessary to pinch themandrel24 at two points in order to displace it along its axis; instead, thegears64 and66 need only apply sufficient lateral loads to maintain themandrel24 at the center of thepassageway78. This eliminates the need to place a constant load on themandrel24 and thus undue stresses thereon. The placement of thegears64 and66 also means that the vertical vibratory forces transmitted to themandrel24 are applied in a symmetrical fashion that alleviates twisting of themandrel24.

Another noteworthy but non-essential feature of the present invention is that the drive racks68 and70 are recessed into the mandrel surfaces74 and76.

This createsridges82 extending along the length of theracks68 and70 that engage thesides64band66bof the drive gears64 and66 to prevent themandrel24 from moving in either direction along an arrow E in FIG. 2; this direction shown by arrow E is orthogonal to the mandrel axis C and to the line D shown in FIG.3.

2. Second Embodiment

A second exemplary elongate member insertion/withdrawal system will now be described with reference to FIG.4. In FIG. 4, components that are the same as those described above with reference to FIGS. 1-3 will be given the same reference character plus one hundred. Such like components will not be described again in detail below.

FIG. 4 shows that securely secured to theupper surface172 of thevibratory housing154 are first and secondhydraulic piston assemblies184 and186. Theseassemblies184 and186 are arranged on opposite sides of themandrel124.Pistons184aand186aare extendable from theassemblies184 and186, respectively, to engageopposite surfaces188 and190 of themandrel124.

Thus, by appropriate application of hydraulic fluid to thepiston assemblies184 and186, thepistons184aand186aof these assemblies can engage themandrel124 to fix the position of themandrel124 relative to thevibratory housing154. This allows the vibratory forces generated by thevibratory assembly130 to be transmitted to themandrel124 primarily through thepiston assemblies184 and186 and only to a lesser extent through thegear drive assembly132. Thepiston assemblies184 and186 can thus alleviate wear on the drive gears164 and166 and the drive racks168 and170 in situations where themandrel124 is only being vibrated and not driven along its axis.

A third exemplary elongate member insertion/withdrawal system will now be described with reference to FIG.5. In FIG. 5, components that are the same as those described above with reference to FIGS. 1-3 will be given the same reference character plus two hundred. Such like components will not be described again in detail below.

FIG. 5 shows that securely mounted onto theupper surface272 of thevibratory housing254 of this third exemplary system are first and secondhydraulic drive assemblies284 and286. Thesehydraulic drive assemblies284 and286 are arranged to apply vertical forces on themandrel224.

In particular, during normaloperation engaging members288 and290 of theseassemblies284 and286 are disengaged from theracks268 and270 and themandrel224 is driven by thegear drive assembly232. However, when the forces generated by thegear drive assembly232 are not sufficient to insert or withdraw themandrel224, the engagingmembers288 and290 engage themandrel224 through theracks268 and270.

Drive piston assemblies292 and294 of thehydraulic drive assemblies284 and286 are then operated to act on themandrel224 through themembers288 and290 and force themandrel224 in either direction along its axis. The forces of thehydraulic drive assemblies284 and286 may be sufficient to insert or withdraw themandrel224 in cases where the forces generated by thegear drive assembly232 are not. Further, thehydraulic drive assemblies284 and286 will be particularly effective when used in conjunction with vibratory forces generated by thevibratory assembly230.

3. Third Embodiment

A third exemplary elongate member insertion/withdrawal system will now be described with reference to FIG.6. In FIG. 6, components that are essentially the same as those described above with reference to FIGS. 1-4 and will be given the same reference character plus three hundred. Such like components will be described below only to the extent that they differ from the corresponding components described above.

As shown in FIG. 6, in this third exemplary system thechannel344 in thesupport base336 is cylindrical. Further, the shock absorbing means380 of theshock absorbing assembly334 are connected between thevibratory housing354 and anintermediate ring392 mounted onto thesupport base336 within thechannel344. Theintermediate ring392 is rotatable about the mandrel axis C relative to thesupport base336. Further, themandrel334 itself is rounded.

In use, theintermediate ring392, and thus thevibratory assembly330,gear drive assembly332, andmandrel324, may be rotated about the mandrel axis C. In certain situations rotation of themandrel324 may be needed to overcome soil conditions and drive themandrel324 into or remove themandrel324 from the ground22. The rounded configuration of themandrel324 facilitates the rotation of themandrel324 about its axis.

4. Fourth Embodiment

Referring now to FIGS. 7-10, depicted at420 therein is yet another wick drain inserting system constructed in accordance with, and embodying, the principles of the present invention.

Theexemplary system420 comprises aninsertion assembly422 that is pivotably connected to anarm424 by apin426. Thearm424 is connected to an excavator, crane, or spotter (not shown) such that theinsertion assembly422 may be moved from place to place. Anactuator assembly428 is connected between theinsertion assembly422 and thearm424. The effective length of theactuator assembly428 may be increased or decreased; operating theactuator assembly428 thus rotates theinsertion assembly422 about the longitudinal axis of thepin426, thereby allowing an angle between theinsertion assembly422 and thearm424 to be changed. Systems other than thearm424, such as those described in the previous and subsequent embodiments, may be used to support theinsertion assembly422.

During use, theactuator assembly428 allows theinsertion assembly422 to be arranged in a proper orientation with respect to the ground. During transportation and storage, the effective length of theactuator member428 may be decreased so that theinsertion assembly422 is folded back substantially parallel to thearm424.

Theexemplary insertion assembly422 comprises a mast orboom assembly430, ahousing assembly432, amandrel assembly434, alinear drive assembly436, avibration assembly438, a suppression assembly440 (FIG.9), and afeed subsystem442.

Thelinear drive assembly436 is arranged to displace themandrel assembly434 along its axis relative to the housing assembly432 (in the direction shown by arrow A in FIG.7). Thelinear drive assembly436 also transfers loads on thehousing assembly432 to the mandrel assembly relative.

Thevibration assembly438 may be operated to cause thehousing assembly436 to vibrate in the direction shown by arrow A. Vibratory forces on thehousing assembly436 are transferred to themandrel assembly434 by themandrel drive assembly436.

The suppression assembly440 connects themast assembly430 to thehousing assembly432 such that thehousing assembly432 may move within a limited range relative to themast assembly430. The purpose of the suppression assembly440 is to inhibit the transfer of the vibratory loads from the housing assembly440 to themast assembly430.

Thefeed subsystem442 is configured to feedwick drain material444 from aroll446 into themandrel assembly434.

Theinsertion system420 operates basically as follows. Thearm424 is moved andactuator assembly428 operated until theinsertion assembly422 is vertically arranged above a desired location at which thewick drain material444 is to be inserted into the earth. Thelinear drive assembly436 is operated to crowd themandrel assembly434 into the earth at the desired location. In many situations, excessive resistance will not be encountered, and thelinear drive assembly436 alone will drive themandrel assembly434 to its desired depth.

Should thesystem420 encounter excessive resistance using thelinear drive assembly436 alone, thevibration assembly438 may be operated. In most cases, excessive resistance can be overcome by the combination of crowding using thelinear drive system436 and the vibratory loads generated by thevibration assembly438. Accordingly, both thelinear drive assembly436 and thevibration assembly438 will be used together whenever excessive resistance is encountered.

Once the excessive resistance is overcome, thevibration assembly438 will be turned off; in general, vibration is hard on equipment and thus should be used only when necessary.

After themandrel assembly434 has been driven to its desired depth, thelinear drive assembly436 will be reversed to withdraw themandrel assembly434 from the ground.

With the foregoing general explanation in mind, the construction and operation of thesystem420 will now be described in further detail.

As perhaps best shown in FIGS. 7 and 9, themast assembly430 comprises afront wall448, aback wall450, afirst side wall452, asecond side wall454, and an interior wall456 (FIG.7). The walls448-54 are joined together to form an elongate box such that the mast assembly has an openupper end458 and an openlower end460. Theinterior wall456 divides the interior of themast assembly430 into aforward compartment462 and arear compartment464. Themast assembly430 further comprises first andsecond side flanges466 and468 that rigidly extend from the first andsecond side walls452 and454 adjacent to the mastlower end460.

FIGS. 7,8, and9 illustrate that thehousing assembly432 comprises afront wall470,back wall472,first side wall474, andsecond side wall476. These walls470-76 are joined together to form a box such that thehousing assembly432 has an openupper end478 and openlower end480 and defines ahousing chamber482.

Themast assembly430 extends through the housingupper end478 and partially into thehousing chamber482. In particular, as perhaps best shown in FIGS. 8 and 9, themast flanges466 and468 and portions of the mast walls448-54 adjacent to theseflanges466 and468 normally reside completely within thehousing chamber482.

The exemplary suppression assembly440 comprises twelveelastomeric members484. As shown in FIG. 8, six of thesemember484 are connected between front surfaces of themast flanges466 and468 and the rear surface of thehousing front wall470. Six of these members are also connected between rear surfaces of themast flanges466 and468 and the front surface of the housingrear wall472.

Theelastomeric members484 allow, but resiliently oppose, a small degree of relative movement between themast assembly430 and thehousing assembly432. Thesemembers484 thus transfer loads between themast assembly430 and thehousing assembly432 but absorb shocks that would otherwise be transmitted between these assemblies. More specifically, theseelastomeric members484 prevent transmission of most vibratory loads and shocks from excessive ground resistance from thehousing assembly432 to themast assembly430. This protects themast assembly432 andarm424 from these shocks.

Referring now to FIG. 10, it can be seen that themandrel assembly434 comprises afront wall486,back wall488,first side wall490, andsecond side wall492. These walls486-92 are joined together in an elongate box such that the mandrel assembly has an openupper end494 and an openlower end496 and defines amandrel chamber498. The front andback walls486 and488 are flat, while theside walls490 and492 are outwardly curved.

Extending from thefront wall486 is a first row ofpins500, and extend from theback wall488 is a second row ofpins502. Thesepins500 and502 extend approximately one-half an inch from and are evenly spaced along the length of the mandrel front andback walls486 and488. In the preferred embodiment, these pins are short hollow tubes secured by welding to themandrel walls486 and488.

Themandrel assembly434 is sized and dimensioned such that it may be received within the mast forwardcompartment462.

Thelinear drive system436 is shown in FIGS. 7,8, and10. Thissystem436 comprises first andsecond gear assemblies504 and506 and first andsecond roller assemblies508 and510. Thegear assemblies504 and506 are mounted onshafts512 and514, and theroller assemblies508 and510 are mounted onshafts516 and518. Thegear assemblies504 and506 are or may be almost identical to each other; similarly, theroller assemblies508 and510 are or may be almost identical to each other. Accordingly, only thegear assembly504 androller assembly508 will be described in detail herein.

As shown in FIG. 10, theshafts512 and516 are connected to inner surfaces of thehousing front wall470 and housingrear wall472. Thegear shaft512 is axially rotated by ahydraulic motor520. Themotor520 is conventional and will not be discussed herein in detail.

Thegear assembly508 comprises first andsecond gear members522 and524 and acenter portion526. Thegear members522 and524 comprise a series ofteeth528 radially extending from theshaft512. Theshafts512 and516 are configured such that thecenter portion526 opposes theroller assembly508.

Thegear center portion526 engages the mandrelsecond side wall492 and theroller assembly508 engages the mandrelfirst side wall490. Thecenter portion526 androller assembly508 are arranged to prevent significant lateral motion of themandrel assembly434 relative to thehousing assembly432.

As shown in FIG. 10, themandrel assembly434 extends between thegear assembly504 and theroller assembly508. In particular, thegear assembly504 straddles themandrel assembly434 such that thegear members522 and524 extend over a portion of the mandrel front andback walls486 and488, respectively. Theteeth528 extend between thepins500 and502 such that movement of theteeth528 is transferred to themandrel assembly434.

Accordingly, when themotor520 axially rotates theshaft512, thegear members522 and524 rotate about the axis of theshaft512; thegear teeth528 engage the mandrel pins500 and502 such that, as thegear members522 and524 rotate, themandrel assembly434 is driven along its longitudinal axis. In particular, with reference to FIG. 8, clockwise rotation of thegear assembly504 will result in upward movement of themandrel assembly434, while counterclockwise rotation of thegear assembly504 will result in downward movement of themandrel assembly434.

In addition, theteeth528 engage thepins500 and502 and thegear center portion526 androller assembly508 engage themandrel side walls490 and492 such that loads on thehousing assembly432 are transferred to themandrel assembly434, and vice versa.

In particular, theteeth528 are contoured such that each tooth extending between two pins is in contact with the pin above and pin below. This transfers vertical loads between thehousing assembly432 andmandrel assembly434 and reduces play in the system when the direction in which themandrel assembly434 is driven needs to be changed. Theroller assembly508 andgear center portion526 have concaveouter surfaces530 and532 that match theconvex side walls490 and492 of themandrel assembly434. And thegear members522 and524 are closely arranged adjacent to the mandrel front andback walls486 and488.

This configuration ensures that front-back, side, and vertical loads are all transferred between the housing andmandrel assemblies432 and434 without substantial movement between these assemblies.

As shown in FIG. 8, thevibration assembly438 comprises a pair ofeccentric weights534 and536 mounted onshafts538 and540 extending between the front and backhousing walls470 and472. A conventionalhydraulic motor542 rotates theweights534 and536 in synchrony in opposite directions to develop a vertical vibratory force that is applied to thehousing assembly432 through theshafts538 and540.

As described above, vertical loads on thehousing assembly432 are applied to themandrel assembly434 by thegear assemblies504 and506 androller assemblies508 and510. Thus, the vibratory forces generated by thevibration assembly438 are transmitted to themandrel assembly434.

Referring again to FIG. 7, it can be seen that thefeed subsystem442 comprises areel assembly544 mounted on ashaft546 extending between to reel struts548 (only one shown in FIG.7). Theroll446 ofwick drain material448 is placed onto thereel assembly544.

Thefeed subsystem442 further comprises upper andlower feed rollers550 and552 mounted on themast assembly430 adjacent to the mast upper and lower ends458 and460, respectively. As shown in FIG. 9, the upper feed roller is mounted on ashaft554 extending between themast side walls452 and454 above an upper edge surface of theinternal wall456. Thelower roller552 is mounted on ashaft556 extending between theside walls452 and454 within amast feed hole558 formed in the mastback wall450. Ahousing feed hole560 is formed in the housing backwall472 adjacent to themast feed hole558.

Thewick drain material444 is fed from theroll446, through thehousing feed hole560 andmast feed hole558, under thelower feed roller552, through therear mast compartment464, over theupper feed roller550, through theforward mast compartment462, through themandrel chamber498, and to the mandrellower end496. At the mandrellower end496, thewick material444 is attached to awick drain shoe562.

With the foregoing more detailed understanding of the construction of thesystem420, the use of thissystem420 will now be described in further detail.

A first operator will be sitting in an excavator or crane from which thearm424 extends. A second operator will be on foot.

The first operator can look down thearm424 towards the housing backwall472. The excavator or crane is basically conventional, so the first operator may control the position of theinsertion assembly422 by operating the excavator or crane and thehydraulic assembly428. The first operator thus arranges theinsertion assembly422 such that the mandrel lower end is located above the desired location where the wick drain material is to be inserted and the mast is at the appropriate angle with respect to vertical.

One of the operators operates thelinear drive assembly436 to rotate thegear assemblies504 and506, thereby crowding themandrel assembly434 into the earth. Because thewick drain material444 is attached to theshoe562, as themandrel assembly434 is crowded into the earth, thewick drain material44 is taken off of theroll446 by thefeed subsystem442 and placed into the earth with themandrel assembly434.

Should themandrel assembly434 encounter excessive ground resistance, the operators will notice thehousing assembly432 begin to move up relative to theboom assembly430 by stretching theresilient members484. At this point, the operator can operate thevibration assembly438; this will cause thehousing assembly432 to move up and down at a rate related to the rotational speed of theweights434. This up and down movement will be transferred to themandrel assembly434, which will help to overcome the excessive resistance and allow themandrel assembly434 to be crowded through the obstruction in the soil. Thevibration assembly438 is then turned off until another obstruction is encountered.

After themandrel assembly434 has been driven to its desired depth, the direction of thelinear drive system436 is reversed to withdraw themandrel assembly434 from the earth. Because theshoe562 is not attached tomandrel assembly434, theshoe562 remains at the desired depth; and because thewick drain material444 is attached to theshoe562, the wick drain material remains in the hole formed by themandrel assembly434.

When themandrel assembly434 is completely withdrawn from the ground, the second operator will cut thewick drain material444 above the ground and attach anew shoe562 thereto. Thesystem420 is then moved to place theinsertion assembly422 at a new desired location, and the process described above is repeated.

The present invention provides a number of advantages over prior art methods.

By keeping the drive and vibration assemblies close to the ground, the mast need not be heavy. This allows potentially taller masts, as the mast only needs to bear the weight of the wick drain material; the linear drive assembly will support the mandrel. The mast assembly may even be constructed with a metal lower portion that is connected to the excavator arm and housing assembly and a plastic upper portion for supporting the wick drain material. With a light mast, the entire system can be made small and transportable, even to the extent that it can be mounted on a conventional excavator or crane with a large vertical mast. And this lightweight mast can be rotated downward for easy transportation and storage.

By driving the mandrel through the center of the vibration assembly, the vibrational loads are symmetrically applied to the mandrel. Such symmetrical loads reduce wear and tear on the mandrel and decrease the chance that the mandrel will fail during vibration.

The mandrel itself has a very small footprint. This is important as it reduces the amount that the mandrel compacts the soil as it is being driven into the earth. Compaction is a problem because it can interfere with flow of water to the wick drain for wicking to the surface.

The arrangement of two gear assemblies each having two gear members helps to balance the loads while the mandrel is being crowded into the ground.

This arrangement also helps ensure that the vibratory loads applied to the mandrel are balanced. The placement of one gear assembly above the other allows the gear teeth to extend over half way between the mandrel pins, thus ensuring a secure transfer of downward motion to the mandrel. The vertically staggered gear teeth also force dirt out from between adjacent mandrel pins, removing dirt that might interfere with the insertion or removal of the mandrel.

This system of the present invention can also be easily manufactured from conventionally available parts.

5. Fifth Embodiment

Referring now to FIG. 11 depicted therein at620 is a wick driving system constructed in accordance with, and embodying, the principles of the present invention. Thissystem620 comprises acrane622, aninsertion assembly624, aspotter626, amandrel628, andwick drain material630.

Thecrane622 is generally conventional in that it has acab portion632 and aboom portion634. Mounted on theconventional crane622 is aroll636 of thewick drain material630.

Attached to the upper end of theboom634 are first andsecond cables638 and640. These cables suspend theinsertion assembly624 above alocation642 at which thewick drain material630 is to be inserted into the earth.

Theinsertion assembly624 is schematically depicted in FIG.11. Additionally, one side of theinsertion assembly624 is not shown so that the operation of theinsertion assembly624 may more easily be described.

In particular, theinsertion assembly624 comprises a fixedplate644 to which thecable638 and640 are connected. Thisfixed plate644 is connected to ahousing646 by asuppression system648 comprising a plurality of elastomer blocks650. Theblocks650 allow thehousing646 to move relative to theplate644.

Mounted within thehousing646 arevibratory members652 and654 that are eccentric and rotate at the same speed in opposite directions such that lateral forces are cancelled and an up and down vibratory force is created. Thesevibratory devices652 and654 are well known in the art and will not be described in detail herein.

Further mounted to thehousing646 are drive gears656 and658. Opposing these drive gears656 and658 arerollers660 and662.

Themandrel628 extends through thehousing646 between thevibratory devices652 and654,drive gear656 androller660, and drivegear658 androller662. Theinsertion assembly624 is symmetrically arranged about themandrel628 such that the vibratory loads created by thevibratory devices652 and654 are applied symmetrically through the drive gears656 and658 androllers660 and662 directly along a longitudinal axis of themandrel628.

The drive gears656 and658 are rotated to crowd themandrel628 into the earth or, in the opposite direction, to remove themandrel628 from the earth. When resistance is encountered, thevibratory devices652 and654 may be operated to impart vibratory loads to themandrel628; these loads assist the insertion/withdrawal of themandrel628. Thevibration suppression system648 inhibits transmission of vibratory loads from thehousing646 to the fixedplate644.

As described above, the upper end of thecrane boom634 is connected by thecable638 and640 to the fixedplate644. Thesecables638 and640, and thus theboom634, are thus also at least partly isolated from the vibratory loads generated by theinsertion assembly624.

Optionally, as shown in FIG. 11, aspotter assembly626 may be connected between thefixed plate644 and thecrane base632. Thespotter assembly626 is conventional and allows theinsertion assembly624 to be moved relative to thecrane base632. Again, thespotter assembly626 is connected to the fixedplate644 and thus is as least partly isolated from the vibratory loads generated by theinsertion assembly624.

Theinsertion assembly624 may thus be positioned above the desiredlocation642 by thecrane622 alone. Thespotter assembly626 will help with precise placement of theinsertion assembly624 and will help to prevent raising of theassertion assembly624 when themandrel628 encounters difficulties while being inserted.

FIG. 11 also shows that thesystem620 may optionally comprise awind sleeve670 and aboom sleeve672. Thewind sleeve670 is attached at its upper end to the uppermost portion of theboom634. The lower end of thewind sleeve670 extends into themandrel628. Thewind sleeve670 thus prevents the wind from acting on the portion of thewick drain material630 that extends between the top theboom634 and the top of themandrel628.

Theboom sleeve672 is attached to theboom634 and provides a channel through which thewick drain material630 passes from theroll636 up to the top of theboom634. Aroller674 may optionally be provided at the top of theboom634 to help feed thewick drain material630 from theboom tube672 into thewind tube670.

FIG. 12 shows that thewind tube670 is hollow and defines awind tube chamber676 through which thewick drain material630 passes. FIG. 12 also shows anupper end678 of themandrel628.

Referring to FIG. 13, depicted therein is alower end680 of thewind tube670. Thislower end680 is at or near asurface682; preferably, but not necessarily, when themandrel628 is fully driven into the earth, at least a portion of thewind tube670 remains within themandrel628.

The embodiment described in FIGS. 11-13 does not require theinsertion assembly624 to support a mast above thelocation642 at which thewick drain material630 is to be inserted. This arrangement also allows thecrane622 to assist in pulling themandrel628 out of the ground by lifting thecables638 and640. Because themandrel628 is not enclosed within a mast or housing, theupper end678 of themandrel628 is exposed and the operator of thesystem620 knows how deep themandrel628 extends into the ground.

Referring now to FIG. 14 depicted therein is yet anotherexemplary system720 for inserting wick drain material into the ground. Thesystem720 comprises amovable truck722, aninsertion assembly724, aspotter assembly726, amandrel728, andwick drain material730. Thesystem720 is similar to thesystem620 described above but does not employ a crane with a boom to support theinsertion assembly724 above a desiredlocation732. Instead, theinsertion assembly724 is entirely supported by thespotter726. In this case, aroll734 of thewick drain material730 is mounted on theinsertion assembly724 and is fed over aroller736 on themandrel728 and then down through themandrel728. Expect for the fact that theroll734 ofwick drain material730 is mounted on theinsertion assembly724, theinsertion assembly724 is constructed and operates in the same basic manner as theinsertion assembly624 described above.

Thesystem720 is highly appropriate for situations in which the wick drain material need not be inserted to a great depth. If the wick drain material is to inserted to a great depth, thesystem620 described above is preferable.

In either case, the location at which the wick drain material is to be inserted need not be sufficiently stable to support the insertion assembly and mandrel. To the contrary, thecrane622 and/ortruck722 may be arranged some distance away from the location at which the wick drain is to be inserted.

6. Indicator System

Referring to FIGS. 15A and 15B, depicted at820 therein is an indicator system that may be used with any of the embodiments above having a vertically extending mast that encloses the mandrel as the mandrel is driven into the ground.

In particular, in FIGS. 15A and 15B, the mandrel is depicted at822 and the mast is depicted at824. Awindow826 is formed along substantially the entire length of themast824, and anindicator828 is formed on anupper end830 of themandrel822. Theexemplary window826 is in the form of a continuous slot that extends substantially along the entire length of themast824. Theindicator828 is preferably painted a highly visible color.

As themandrel822 is driven into the earth, theupper end830 thereof moves downward. If the mast is entirely closed, the mandrelupper end830 is not visible and the operator does not know how far themandrel822 has been driven into the earth. With theexemplary system820, theexemplary indicator828 is a projection that extends out of themast824 through thewindow826 and is thus clearly visible to the operator. The operator thus has a clear visual indication of how far themandrel822 has been driven into the earth.

Theindicator828 need not be a projection, however. The mandrelupper end830 will be visible through theslot826 without a projection or being painted and thus may serve the function of theindicator828. Painting the mandrel upper end830 a highly visible color will help the operator to see this upper end through theslot826. And if theindicator828 does not extend out of themast824, thewindow826 need not be a continuous slot, but may instead be formed by a series of holes that allow the operator to view the mandrelupper end830 and thus theindicator828.

From the foregoing, it should be clear that the present invention may be embodied in forms other than those described above. The above-described systems are therefore to be considered in all respects illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description. All changes that come within the meaning and scope of the claims are intended to be embraced therein.

Claims (16)

What is claimed is:

1. A drive system for inserting into the ground an elongate member defining a member axis, comprising:

a support plate;

a support system that engages the ground and supports the support plate at a substantially fixed height above a desired location;

an insertion housing defining an opening through which the elongate member passes as the elongate member is driven into the ground;

a suppression system operatively connected between the support plate and the insertion housing to support the insertion housing above the desired location and resiliently oppose relative movement between the support plate and the insertion housing;

at least one drive gear mounted to the insertion housing, where the drive gear engages the elongate member such that rotation of the drive gear displaces the elongate member along the member axis;

a vibratory system for creating vibratory forces, where the vibratory system is substantially symmetrically arranged within the insertion housing relative to the member axis such that vibratory forces created thereby are transmitted to the elongate member through the at least one drive gear substantially along the member axis; wherein

rotation of the drive gear crowds the elongate member into the ground,

operation of the vibratory system vibrates the elongate member into the ground, and

rotation of the drive gear and operation of the vibratory system together crowds and vibrates the elongate member into the ground.

2. A drive system as recited inclaim 1, in which:

a drive rack is formed on opposing surfaces of the elongate member; and

the at least one drive gear engages the drive rack.

3. A drive system as recited inclaim 1, further comprising at least one drive roller that engages the elongate member in opposition to the at least one drive gear.

4. A drive system as recited inclaim 1, in which the vibratory system comprises first and second eccentric weights substantially symmetrically arranged on either side of the elongate member.

5. A drive system as recited inclaim 1, in which the support system comprises:

a support base that engages the ground; and

a spotter assembly operatively connected between the support base and the support plate.

6. A drive system as recited inclaim 5, in which the support system further comprises a boom operatively connected between the support base and the support plate.

7. A drive system as recited inclaim 1, in which the support system comprises:

a support base that engages the ground; and

a boom operatively connected between the support base and the support plate.

8. A drive system as recited inclaim 1, in which:

the support system comprises a support base that engages the ground; and

the elongate member is a mandrel for carrying wick drain material into the ground, where a supply of wick drain material is supported by the support base.

9. A drive system as recited inclaim 1, in which the elongate member is a mandrel for carrying wick drain material into the ground, where a supply of wick drain material is supported by the support plate.

10. A drive system as recited inclaim 1, in which the elongate member is a mandrel for carrying wick drain material into the ground, the drive system further comprising a wind sleeve that protects at least a portion of the wick drain material above the elongate member.

11. A drive system as recited inclaim 1, in which the support plate is arranged above the at least one drive gear.

12. A drive system as recited inclaim 1, in which:

the elongate member is a mandrel for carrying wick drain material into the ground; and

the drive system further comprises a mast extending from the support plate above the insertion housing for supporting the mandrel above the desired location; wherein

at least one opening is formed in the mast to allow visual location of the mandrel within the mast.

13. A drive system for inserting into the ground a mandrel for carrying wick drain material, comprising:

a support plate;

a support system that engages the ground and supports the support plate at a substantially fixed height above a desired location;

an insertion housing;

a suppression system operatively connected between the support plate and the insertion housing to support the insertion housing above the desired location and resiliently oppose relative movement between the support plate and the insertion housing;

at least one drive gear mounted to the insertion housing, where the drive gear engages the mandrel such that rotation of the drive gear displaces the mandrel along its longitudinal axis;

a vibratory system for creating vibratory forces, where the vibratory system is mounted to the insertion housing such that the vibratory forces are transmitted to the mandrel through the at least one drive gear;

a mast extending from the support plate above the insertion housing for supporting the mandrel above the desired location, where at least one opening is formed in the mast to allow visual location of the mandrel within the mast; wherein

rotation of the drive gear crowds the mandrel into the ground,

operation of the vibratory system vibrates the mandrel into the ground, and

rotation of the drive gear and operation of the vibratory system together crowds and vibrates the mandrel into the ground.

14. A drive system as recited inclaim 13, in which a projection is formed on an upper end of the mandrel, where the projection extends through the opening formed in the housing to allow visual detection of the upper end of the mandrel within the mast.

15. A drive system as recited inclaim 13, in which an upper end of the mandrel is painted to enhance visual detection of the upper end of the mandrel within the mast.

16. A drive system as recited inclaim 13, in which the projection is painted to enhance visual detection of the upper end of the mandrel within the mast.

Images